MXPA05012640A - Membrane pipe module - Google Patents

Abstract

The invention relates to a membrane pipe module, said module comprising a cylindrical housing (102) containing a plurality of tubular membrane sections (104) which extend in the axial direction and are interconnected at the ends (105, 105') thereof, forming longer tubular membrane sections. Said cylindrical housing (102) comprises a heatable chamber (110), on one or both sides, comprising U-shaped connection pipes (115) which are arranged therein and are guided through a separating wall (117, 114) between the chamber (110) and the housing (102), with the twoopen ends thereof, and respectively connect two adjacent open tubular membrane sections (112, 112'), forming a membrane loop.

Description

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VcrsOeiiUichl; - thousand iiitvrnotltmttbsm ItGchsrch nberichi MEMBRANE PIPE MODULE DESCRIPTION OF THE INVENTION The invention relates to a membrane tube module with integrated heat exchanger. In the membrane technology for the separation of mixtures of liquids and gases, the used membranes are grouped in convenient arrangements forming modules. Forms of these modules of public knowledge are the modules of membranes in folds, in plates and rolled on one side, as well as the modules of hollow fiber, capillary and tubular or tube. The group of modules mentioned first is used for flat membranes, and the second group for tubular-shaped membranes. The diameters of the individual membrane hoses vary. In the case of the hollow fiber module they are located between 30 and 100 μm, in the case of the capillary module in the area of 0.2 to 3 mm and in the tubular or tube module in the area of 4 to 50 mm. The current through the membrane is directed, in the case of hollow fibers, from the outside to the inside, in capillary membranes it can be done both from the inside out and from the outside in and in tubular membranes it is oriented, generally from the inside out . In the tubular or ceramic module, the tube rests in the form of a hose on the inner face of pressure-resistant support tubes, the material of the support tubes being able to have sufficient porosity and be permeable to the percept. If the material of the support tube itself is impermeable to the permeate, then the support tube must have a sufficient number of perforations (openings) for the exit of the permeate. In this case it is convenient to place a thin porous tube between the support tube and the membrane, for example of porous polyethylene, which on the one hand does not prevent the lateral transport of the permeate to the perforations arranged at short distances in the support tube and on the other, it offers the membrane, particularly in the region of these perforations, the appropriate support. The membranes are applied interchangeably or also fixed on the support material. Due to the construction described, it was imposed in the technique for modules with hose-shaped membranes with indicated diameters (generally in the area between 4 and 50 mm, which are designated in the technology as tubular membranes) that are provided with a layer of support, the designation tube module, whereby in the following the designation tube module for modules with tubular membranes is used. The tubular membranes of a tube module Ge '- - Cl /, depending on the method in each case, or two or more tubular membranes are passed in parallel. It is possible, therefore, depending on the requirements of the process, to perform any combination of step in parallel or in series. In accordance with the particular configuration of the tubular membranes, they are used, for example, for the micro, ultra and nanofiltration methods or for the reverse osmosis and pervaporation methods, respectively steam permeation. In the pervaporation method for the separation of liquid mixtures, the heat necessary for the evaporation of the sensible heat permeate of the liquid mixture is extracted, being that the reduction of temperature, produced in this way, produces a reduction of the driving force and of the current passing through the membrane and with this the power of the method. In the separation of vapor mixtures or gases, due to unavoidable heat losses, cooling and condensation of components of the mixture can occur, which in turn can cause a blockage of the membrane. Therefore it is necessary to feed the lost heat to the mixture that must be separated as continuously as possible. In the known tube modules, the heat supply is carried out in stages ";-? .3 i "3 c the initial mix is to be separated out of the module in interconnected heat exchangers After leaving the heat exchanger and entering the initial mix into the 'tube module Heat can no longer be fed according to previous technology, particularly in tube modules with very long membrane hoses, respectively large membrane surface and a large volume of permeate, considerable cooling of the initial mixture may occur, Therefore, only modules with a limited surface area can be used, between which a heat exchanger must be connected, the unavoidable delimitation of the membrane surface per module and the required number of heat exchangers. heat, the additional piping required between these devices and the additional control device has the consequence, in particular in the case of ma ers, an ineconomic increase in the specific costs per installed membrane area. From the above, the object of the invention is immediately derived. This objective is achieved by means of a membrane tube module in which a multiplicity of tubular membrane sections, extending in the axial direction and which are eventually partially connected to each other in their xtmos ra ra or se cio es ce m. arranged in a cylindrical casing, characterized in that the cylindrical casing comprises on one or both sides a heatable chamber with U-shaped connection tubes arranged therein which pass with their two open ends through a partition wall between the chamber and the housing and respectively connecting two open sections of adjacent tubular membrane forming an endless membrane cycle. In the known membrane tube modules, the tubular membrane sections, which extend into the cylindrical housing, are connected at their ends to form an endless membrane hose. The inventive tube module differs from the above because a certain amount of adjacent tubular membrane sections remains open at one end of the cylindrical housing, or also at both ends, and these ends are then connected to the connection tubes in the form of U passing through their open ends through the partition wall between the chamber and the housing. At these connection points, the mixture, which must be separated, then passes through the heatable chamber, which ensures the necessary heat supply. That is to say, the chamber has the function of a heat exchanger, whereby the heat supply can be carried out, for example, by means of steam or another calender carrier. In a particular embodiment of the inventive tube module, the tubular membrane sections are fixed at one end, or also at both ends, on a plate provided with perforations. The open ends of the U-shaped connecting tubes pass through these perforations, and - of course - a seal must be provided. Tubular membrane sections that are not connected to the heat exchanger can be connected inside the housing or, in the case of fixing by perforations in the end plate, with corresponding perforations in the end plate. The cylindrical housing of the tube module is, for example, made of steel or another metal, optionally also of synthetic material, with corresponding drainage openings for the permeate produced. The heatable chamber serving as a heat exchanger has corresponding inlet and outlet openings for the heat carrier. In case the heat carrier is steam, the chamber is configured correspondingly to temperature and pressure test, preferably steel. In a preferred embodiment, heatable chambers are provided on both sides of the cylindrical casing as heat exchangers. Each chamber can be provided with a corresponding device for temperature regulation. If there are heat exchangers on both sides of the cylindrical housing, then at least one of these chambers must be provided with corresponding conduits for the inlet and outlet of the fluid that must be treated in the module. In a preferred embodiment, the chambers provided on one or both sides are configured as separable installations. This facilitates the exchange of damaged tubular membrane sections in case of interruptions. The inventive tube module is suitable for all tubular membranes, namely for the classic type with support tube in which the support tube is permeable to the permeate or, in the case of impermeable support tube, a porous tube is inserted extra thin between the support tube and the membrane. On the other hand and preferably also for those membranes in which the membrane layer, the support layer and optionally an additional carrier layer already form a unit. For the separation of liquid mixtures according to the pervaporation method, multilayer membranes consisting of at least two layers of different chemical composition are preferably used for this, wherein a carrier layer of non-woven or woven material optionally also exists. Such composite or ccr membranes. these swan ::, er. general, •;:. = ca inferi r: r: I know that it is essentially responsible for the mechanical resistance of the membrane (support layer), and a layer that is on top of it with different chemical properties that essentially determines the separation properties of the membrane (separating layer). Preferably, a carrier layer of non-woven or woven material is additionally located below the support layer. Such composite membranes, which are used as flat membranes for the separation of difficult-to-remove liquid mixtures by distillation according to the pervaporation method, respectively the vapor per ation or for the gas separation, are known from EP-B-0 096 339. These flat membranes are used, after deformation to a tube membrane, in a preferred embodiment of the inventive tube module. The tubular membranes have diameters in the area between 4 and 50 mm and preferably between 8 and 30 mm, with diameters between 12 and 35 mm being particularly advantageous for the practice. In a particular embodiment, the tubular membrane is covered or wrapped by fabric, after its formation, with one or more outer layers of non-woven or woven material, so that the tubular membrane already has sufficient pressure resistance and can be applied in he The invention is explained below by the drawings. Fig. 1 shows, in this, a module according to the present invention with a heatable chamber on only one side and Fig. 2 a similar one with respectively a heatable chamber on both sides of the module. The module 101 according to Fig. 1 comprises a housing 102 cylindrical with a multiplicity of support tubes 103 in the axial direction with sections 104 of tubular membrane. In an alternative (not shown) tubular membrane sections are used with sufficient pressure resistance without support tubes. The cylindrical housing 102 is provided with at least one connection 120 for draining the permeate that passes through the tubular membrane. In Fig. 1 respectively an end 105 of a tubular membrane section 104 is fixed on one side of the module 101 in a perforation 108 of a separation wall 107 and connected to the end 105 'of a second section 104' of tubular membrane, which is fixed in a perforation 108 'in the separation wall 107, by means of a connecting element 106. In Fig. 1, this connecting element 106 is a U-shaped tube elbow, but it can also be a corresponding notch in a final plate 109. In FIG. It is therefore possible to also connect several sections of tubular membrane through such notches. Between the final plate IC3 and the network 107 e separation there are corresponding seals (not shown). On the other side of the module 101 is a heatable chamber 110 with connections 111, 111 'for the input and output of a heating means. One end of the tubular membrane section 112 is fixed in a bore 113 of a separation wall 114 and connected by a U-shaped connecting tube 115 to the end 112 'of a second tubular membrane section 104', fixed in a perforation 113 'of the partition wall 114. The length of the U-shaped connecting tube 115 is selected such that sufficient heat transfer is ensured to the separate mixture passing through the U-shaped connecting tube 115. The U-shaped connecting tube 115 it can be fixed, in turn, in perforations 116, 116 'of a final plate 117. Then a corresponding seal (not shown) is located between the end plate 117 and the partition wall 114. Through the heatable chamber 110 pass ducts 118, 118 'with connections 119, 119' for the entry and exit of the mixture to be separated. Figure 2 shows a module 201 according to the present invention with two heatable chambers 210a, 210b. In this case a cylindrical casing 202 of the module 201 contains an axially extending buffer tube 3C2 with tubular membrane sections 204. In an alternative embodiment (not shown), tubular membranes with sufficient pressure resistance without support tubes are applied. The cylindrical housing 202 of the module 201 is provided with at least one connection 220 for draining the permeate that passes through the tubular membrane. Each tubular membrane 204 is fixed at both ends 205a, 205b in perforations 208a, 208b of a separation wall 207a, 207b. To each perforation 208a, 208b, in the separation wall 207a, 207b corresponds a perforation 213a, 213b in a final plate 217a, 217b. In the perforations 213a, 213b of the end plates 217a, 217b on the side, which is not oriented towards the wall 207a, 207b, there are fixed U-shaped connecting tubes 215a, 215b connecting respectively two perforations 213a, 213a '; 213b, 213b 'on the final plate 217a, 217b and with this respectively two ends 205a, 205a', 205b, 205b 'of sections 204 of tubular membrane. A seal (not shown) is optionally located between the partition wall 207 and the end plate 217. The U-shaped connecting tubes 215 project into the interior of the heating chambers 210; its length determines the volume of heat that must be transferred through the surface to the fluid mixture by separating it home by them. The 210th cameras, 210b of heating are provided with connections 211a, 211a ', 211b, 211b' for the input and output of the respective heating means. Through at least one of the chambers (here 210a) heatable pass conduits 218a, 218a 'with connections 119a, 119a' for the inlets and outlets of the mixture to be separated. In a particular embodiment, connections corresponding to the connections 119a, 119a 'are also provided on the right side of the module. For industrial application, a module according to the present invention offers considerable advantages. In the modules, used so far for the separation of fluid mixtures according to the pervaporation method, the membrane area that can be conveniently installed in a module unit is limited, due to excessive cooling due to the need to avoid evaporation of the permeate and with this an excessive reduction of the flow. In the module according to the present invention, this limitation ceases to exist, since it is carried out, after the passage of the fluid mixture by separating through a limited section of tubular membrane, a heating in the heatable chambers by means of heat exchange. In this, any loss of heat is immediately replaced, the membranes are operated at almost constant high temperatures and with this with an optimal use of the current. This allows, especially in the pervaporation method, a clear reduction of the required membrane surface and a reduction in costs. Thanks to the omission of pipe between separate modules and heat exchangers, another cost saving is produced. In the vapor permeation and gas permeation methods, the condensation of components of the inlet mixture on the membrane surface is prevented and with this a blocking of the membrane and an inhibition of the transport passing through the membrane.

Claims (6)

1. Membrane tube module in which are arranged in a cylindrical housing a multiplicity of tubular membrane sections extending in the axial direction and which are possibly connected to each other in part at their ends forming sections of longer tubular membrane, characterized in that the Cylindrical housing comprises a heatable chamber on one or both sides with U-shaped connection tubes disposed therein that pass with both ends open by a partition wall between the chamber and the housing and which respectively connect two sections of tubular membrane adjacent openings forming an endless membrane cycle.

2. Membrane tube module according to claim 1, characterized in that the tubular membrane sections have a diameter in the area between 12 and 25 mm. Membrane tube module according to claim 1 or 2, characterized in that the tubular membrane sections are coated or wrapped by fabric with one or more outer layers of nonwoven or woven material, so that they have a greater resistance to pressure and they can be used in the modules without a support tube. 4. Membrane tube module according to one of the preceding claims, characterized in that the tubular membrane is a composite membrane suitable for pervaporation. Membrane tube module according to one of the preceding claims, characterized in that the heatable chambers provided on one or both sides are designed as removable installations. 6. Use of the membrane tube module according to one of claims 1 to 5 for the separation of liquid mixtures according to the pervaporation method.